Among vehicles that are chargeable by means of a charging cable from a power supply external to the vehicles, a vehicle is known that is capable of communicating with a device external to the vehicle by using, as a communication channel, a charging port to which a charging cable is connected as well as the charging cable.
For example, Japanese Patent Laying-Open No. 2009-153015 (PTL 1) discloses a power line communication (hereinafter also referred to as “PLC”) system using a charging cable. In this PLC system, in response to connection of a plug 20 of the charging cable to a receptacle external to a vehicle, a vehicle-mounted navigation system 15 and a user's personal computer at home are enabled to communicate data through the power line. While data communication is done between the home personal computer and the vehicle-mounted navigation system 15, a notification unit 25 of the plug 20 is controlled by the vehicle-mounted navigation system 15 to indicate the ratio of an amount of data having already been received by the vehicle-mounted navigation system 15.
According to this PLC system, whether or not data transmission between the vehicle-mounted device and the device external to the vehicle is close to completion can easily be confirmed by a user (see PTL 1).